Connection of tubes of dissimilar metals



L.'BREGUET. CONNECTION 0F TUBES 0F DISSIMILAR METALS.

APPLICATION FILED may. 2, 191a.

Patented July 20, 1920.

UNITED STATES PATENT OFFICE.

LOUIS BREGUET, OF VELIZY, FRANCE, ASSIGNOB. T0 SOCIETE ANONYME DES ATELIERS DAVIATION LOUIS BREGUET,

0F VELIZY, SEINE-ET-OISE, FRANCE.

Specification of Letters Patent.

Patented July 20, 1920.

Application filed November 2, 1918. Serial No. 260,904.

To all whom it may concern.-

Be it known that I, LOUIS BREGU'ET, a citi- Zen of the Republic of France, residing in Velizy, Seine-et-Oise, France, have invented certain new and useful Improvements in the Connection of Tubes of Dis simllar Metals, of which the following is a specification.

This invention has for its object to provlde very efficient connection of metal tubes and construction of tubular metal framework and the like, and is more especially intended for employment in joining tubes of aluminium, or of aluminium alloy, by means of steel connecting pieces and, in describing the invention we will presume that it is so employed.

In uniting such dissimilar metals by means of screwthreading, soldering or otherwise, there is encountered the difficulty that there is formed between the different metals an electrical couple which although very feeble, leads to the rapid disaggregation of the metals in intimate contact, and eventually destroys the connection, with the risk of causing seriousaccidents. Further, in the case of tubes of aluminum or aluminum alloys, which are produced by drawing, it is extremely difiicult, or even impossible, to calibrate them to the exact diameter of the connecting pieces, so that there exists a play between the screwthreads and the connecting fittings.

To overcome these disadvantages, the present invention introduces the use as a solder or filling between the juxtaposed surfaces of the tube and junctionpiece, of sulfur applied in molten condition, so that it fills even the most minute spaces and serves not only to effect a firm mechanical e'ngagement whereby looseness or play is avoided, but also serves as a dielectric to prevent electrolytic action between the dissimilar metals.

The following description with reference to the accompanying drawing of how the invention can be applied to the construction of the frame of the small boat of an airship will enable the nature of this invention and how it can be carried into efiect to be understood. v

Figure 1 represents the various members of the frame partly put together and Figs. 2, 3 and 4 show, respectively (drawn to a larger scale) side, end, and plan views of one of the connecting pieces.

The tubes A, may be, for instance, of the aluminium alloy known as duralumin and circular in cross-section the outer surfaces of their extremities being roughened or striated, as shown at a.

The connecting pieces B may be of steel and these are roughened or striated on their inner surface as shown at Z).

The tubes A, are engaged in the small tubular projections of the connecting-pieces B and are firmly fixed therein by means of sulfur brought to a liquid state by heat.

The great fluidity of molten sulfur allows it to fill up the smallest cavities which there may be in the. roughened or striated surfaces and also to fill up any free. space be tween the tubes A and the connectingpieces B.

Although we have shown the tubes, and connecting-pieces B circular in cross-section, they may be of any other shape which may be desired.

This process allows of the employment, on a large scale, in aeronautical work, of the light aluminium alloy which is known as duralumin. This alloy may vary in composition according to the following percent ages.

lVhat is claimed is 1. In a tubular structure comprising tubes and connecting pieces of dissimilar metals, the combination of a tube and connecting piece, the latter having a socket receiving the end of the former, and sulfur filling the space between their contiguous surfaces and serving as a dielectric to prevent electrolytic action.

2. In a tubular structure comprising tubes and connecting pieces of dissimilar metals, the combination of a tube striated at its end, with a connecting piece having a socket receiving such striated end, and sulfur filling the space between their contigu ous surfaces.

3. In a tubular structure, the combination of a tube of aluminium alloy, striated at its vs'ocl'iets makin a loese lit with the tubes, end, With a connecting piece of steel, receivthe contiguous surfztces of the tubes and ing such striated end, and sulfur filling the sockets being striated, and sulfur filling the 10 space between their contiguous surfaces. space betwi're'en aces. i

4. In '21- tubular struct'uf'e comprising In Witness Whred'i, I 'h'ztv' hereunto tubes and connecting pieces havin sockets signedmy name. I for receiving the J ends of the tufies; such 7 Y LOUIS BREGUET. 

